Fuel injection valve

Abstract

A fuel injector (1), in particular for the direct injection of fuel into the combustion chamber of a mixture-compressing, spark-ignited internal combustion engine includes an actuator (10), a valve needle (3) actuatable by the actuator (10) for operating a valve-closure member (4), which, together with a valve-seat surface (6) forms a sealing seat and a swirl disk (35) having at least one swirl channel (36). An elastic fuel metering ring (37) is situated in a recess (43) of a nozzle body (2) of the fuel injector (1) in such a manner that a metering cross-section of the at least one swirl channel (36) is variable as a function of a fuel pressure prevailing in the fuel injector (1) during operation.

Description

BACKGROUND INFORMATION[0001] The present invention is directed to a fuel injector according to the definition of the species in the main claim.[0002] A fuel injector for the direct injection of fuel into the combustion chamber of a mixture-compressing, spark-ignited internal combustion engine, the fuel injector including a guide and seat area formed by three disk-shaped elements at the downstream end of the fuel injector is known from German Patent Application 197 36 682 A1. A swirl element is embedded between a guide element and a valve seat element. The guide element is used to guide an axially movable valve needle that passes through the guide element while a valve closing section of the valve needle cooperates with a valve-seat surface of the valve seat element. The swirl element has an inner opening area with multiple swirl channels that are not connected to the outer circumference of the swirl element. The entire opening area extends completely across the axial thickness of th...

AI Technical Summary

Benefits of technology

[0004] In contrast, the advantage of the fuel injector according to the present invention having the characterizing features of the main claim is that it is possible to adjust the swirl as a function of the operating state of the fuel injector, making it possible to produce a jet pattern adapted to the operating state of the fuel injector. This makes it possible to optimize both the mixture formation and the combustion process.[0005] The jet apex angle is advantageously influenced by the pressure of the fuel flowing through the fuel injector which, through an elastic fuel metering ring, produces a variable throttle effect according to the operating state and thus makes it possible to have a direct influence on the swirl intensity.[0006] The measures cited in the dependent claims make advantageous refinements on and improvements of the fuel injector specified in the main claim possible.[0007] A particular advantage in this connection is the simple and cost-effective shape of the fuel metering ring, which may be easily made from an elastic material and inserted without difficulty into standard fuel injectors having conventional swirl formation.[0008] A particular advantage is the flexibility in the choice of the swirl disk since the jet pattern remains formable due to a varied shape and number of swirl channels and nonetheless it may be adapted to the operating state.[0009] A further advantage is that the measure according to the present invention also makes it possible to adjust the steady-state flow through the fuel injector, making it possible to reduce variations in the steady-state flow, which in turn has a positive effect on fuel consumption and exhaust gas values.

Problems solved by technology

A disadvantage of the fuel injectors known from the publication cited above is in particular the fixedly set swirl angle, which cannot be adapted to the different operating states of an internal combustion engine such as partial load and full load operation.

As a result, it is also not possible to adapt the cone apex angle of the injected mixture cloud to the various operating states, which results in non-homogeneities during combustion, increased fuel consumption, as well as increased exhaust gas emission.

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